Blair Ainslie believes offshore wind will bring a new era of prosperity to the port – “there will be signs of the upturn within two to three years” – and sees his present workforce of 260 expanding to 450 by the end of next year.

He said Seajacks had been strengthened financially by new owners Marubeni Corporation and the Innovation Network of Japan, who acquired Seajacks in 2012, and sees the firm increasing its fleet of hi-tech jack-up vessels from three – with two on order – to 10 within the next decade.

Starting out in 2006 with little more than an idea for self-propelled jack-up vessels – in place of ones needing to be towed into position by tugs – he has turned his vision into a company with a fast-rising turnover of $120 million (£75 million).

The versatility of the design is highlighted by the fact that while Seajacks’ first £75m vessel Kraken has been working for Shell in Southern North Sea gas field work since it was built in 2009, its twin, Leviathan, has been put to work in offshore wind, most recently installing turbines on the German Meerwind project in the North Sea.

Vessel number three Zaratan – “she is mainly designed for offshore wind but still has the capacity for oil and gas” – arrived in 2010 and has also been directed at the Meerwind project.

Mr Ainslie said: “Our fourth vessel Hydra will be arriving in June and will be deployed in oil and gas or operational maintenance work in offshore wind.

“Our fifth vessel Scylla, being built by Samsung in Korea, will be arriving in the fourth quarter of next year.

“She is twice the size of Zaratan, with a displacement of 28,000 tonnes and a 1,500 tonne crane, and has been designed to build round three wind farms projects.”

He said they had been talking to the firms who would be developing the giant East Anglia Array windfarm and other avenues for local work included the extension to the Greater Gabbard windfarm – Galloper – and the planned Dudgeon windfarm north of Cromer.

Mr Ainslie said: “We have an option for a second vessel of the same design as Scylla and will consider it once we get some political certainty about the government’s EMR (Electricity Market Reform) and stability in the financial markets.

“We are not going to stop at six vessels. Marubeni are big people in offshore wind and very supportive of us. Each time we acquire a new vessel takes our workforce up by 70 to 80 people.”

Seajacks moved into new £4m headquarters on the South Denes Business Park 18 months ago and has become the flagship tenant of the port’s new enterprise zone.

Mr Ainslie hopes assisted area status will also soon be confirmed for the area as an additional lever for economic expansion.

“Yarmouth is an island with significant poverty in a wealthy area and does deserve assisted area status,” he said.

“However, it is my view that the town has a lot to offer even without the help. The whole supply chain for work in the Southern North Sea can be found here and a number of firms have strong experience in offshore wind.

“Apart from the manufacture of turbines we can build wind farms just using companies in Yarmouth.”

Mr Ainslie said despite the current lack of certainty coming from central government, companies remained confident about the future of round three windfarms and “we have three of the biggest in the world on our doorstep”.

However, he said his vision for Seajacks extended right round the world in both oil and gas and offshore wind.

They were marketing their services in such Far East countries as Korea and Japan which were playing catch-up in offshore wind and also looking at the North American market.

Mr Ainslie said the Meerwind windfarm had seen the firm take on more of a project management role and the aim was to develop that turn-key capability in future schemes.